A direct approach to quaternionic manifolds

The recent definition of slice regular function of several quaternionic variables suggests a new notion of quaternionic manifold. We give the definition of quaternionic regular manifold, as a space locally modeled on $\mathbb{H}^n$, in a slice regular sense. We exhibit some significant classes of examples, including manifolds which carry a quaternionic affine structure.Comment: 13 page

The Role of Vision on Spatial Competence

Several pieces of evidence indicate that visual experience during development is fundamental to acquire long-term spatial capabilities. For instance, reaching abilities tend to emerge at 5 months of age in sighted infants, while only later at 10 months of age in blind infants. Moreover, other spatial skills such as auditory localization and haptic orientation discrimination tend to be delayed or impaired in visually impaired children, with a huge impact on the development of sighted-like perceptual and cognitive asset. Here, we report an overview of studies showing that the lack of vision can interfere with the development of coherent multisensory spatial representations and highlight the contribution of current research in designing new tools to support the acquisition of spatial capabilities during childhood

Comparison of Distances for Supervised Segmentation of White Matter Tractography

Tractograms are mathematical representations of the main paths of axons within the white matter of the brain, from diffusion MRI data. Such representations are in the form of polylines, called streamlines, and one streamline approximates the common path of tens of thousands of axons. The analysis of tractograms is a task of interest in multiple fields, like neurosurgery and neurology. A basic building block of many pipelines of analysis is the definition of a distance function between streamlines. Multiple distance functions have been proposed in the literature, and different authors use different distances, usually without a specific reason other than invoking the "common practice". To this end, in this work we want to test such common practices, in order to obtain factual reasons for choosing one distance over another. For these reasons, in this work we compare many streamline distance functions available in the literature. We focus on the common task of automatic bundle segmentation and we adopt the recent approach of supervised segmentation from expert-based examples. Using the HCP dataset, we compare several distances obtaining guidelines on the choice of which distance function one should use for supervised bundle segmentation

Development and validation of flight control laws for a small-scale helicopter

University of Pisa is performing a research finalized to develop Rotary Unmanned Aerial Vehicles (RUAV) starting from a small commercial RC helicopters. These vehicles will be capable to perform planned missions in autonomous or automatic flight, including the take-off and landing phase, also thanks to sense and avoid system capabilities. At the moment the activities are focused on a small helicopter, T_REX 500 ESP equipped with a GPS, inertial sensor and a data acquisition system, avaiable at the department. In the first part of this work, a non-linear open-loop analytic model of the rotor craft (developed and identificated in a previous thesis at the department)will be modified and linerized. The procedure of linearization is based on a Matlab automatic tool which creates a linear model directly from the non-linear one. In the second part of this work the control laws will be evaluated and compared with the corresponding laws created for a model based on the aerodynamic derivatives (developed in a previous thesis)in order to understand better the dynamic of the helicopter. As a final validation the control laws will be implemented on the non linear model to verify the stability and the beahaviour of the T-Rex 500 after inputs in velocity (capability to reach a new condition of trim)

DEVELOPMENT OF AN IN VITRO BIOMIMETIC DEVICE AIMED AT REPRODUCING THE INTESTINAL BARRIER

Lo scopo della tesi è il design e la caratterizzazione di un sistema biomimetico di simulazione in vitro della barriera intestinale. Il device simula le proprietà della barriera intestinale sia in termini di interfaccia permeabile che consente il trasporto di sostanze e l'assorbimento di farmaci, sia come attuatore bioibrido ingegnerizzato che riproduce la peristalsi intestinale. Lo scopo del lavoro nasce dalla necessità di avere uno strumento in vitro per modellare le caratteristiche fisiologiche e patologiche della barriera intestinale e i meccanismi di assorbimento attraverso di essa

Il ruolo della metodica CGH array nella diagnostica delle sindromi dismorfogenetiche con disabilità neuropsichica in eta evolutiva

La tesi è strutturata in una parte generale che tratta le sindromi dismorfogenetiche e la disabilità intellettiva e le modalità più innovative di diagnosi. La parte sperimentale si concentra su pazienti affetti da disturbi del neurosviluppo e/o anomalie congenite multiple di natura da determinare studiati al CGH array. In maniera esemplificativa, viene poi studiato un campione di pazienti affetti da sindrome Di George

Assessment of Alexithymia : Pychometric Properties of the Psychological Treatment Inventory-Alexithymia Scale (PTI-AS)

The aim of this study is to investigate the psychometric properties of a new measure of alexithymia, the Psychological Treatment Inventory-Alexithymia Scale (PTI-AS)

Allocentric spatial perception through vision and touch in sighted and blind children.

Abstract Vision and touch play a critical role in spatial development, facilitating the acquisition of allocentric and egocentric frames of reference, respectively. Previous works have shown that children's ability to adopt an allocentric frame of reference might be impaired by the absence of visual experience during growth. In the current work, we investigated whether visual deprivation also impairs the ability to shift from egocentric to allocentric frames of reference in a switching-perspective task performed in the visual and haptic domains. Children with and without visual impairments from 6 to 13 years of age were asked to visually (only sighted children) or haptically (blindfolded sighted children and blind children) explore and reproduce a spatial configuration of coins by assuming either an egocentric perspective or an allocentric perspective. Results indicated that temporary visual deprivation impaired the ability of blindfolded sighted children to switch from egocentric to allocentric perspective more in the haptic domain than in the visual domain. Moreover, results on visually impaired children indicated that blindness did not impair allocentric spatial coding in the haptic domain but rather affected the ability to rely on haptic egocentric cues in the switching-perspective task. Finally, our findings suggested that the total absence of vision might impair the development of an egocentric perspective in case of body midline-crossing targets

Failure in reflective functioning as a key factor in the association between problematic social networking sites use, attachment and childhood maltreatment: A network analysis approach on gender differences

Following a network analysis approach, the present study aims to explore the pattern of mutual relationships between failure in reflective functioning (RF) - defined as hypomentalization - problematic social networking sites use (PSNSU), attachment anxiety and avoidance, and childhood maltreatment among emerging adults, with a focus on gender differences. The study sample comprises N = 1,614 emerging adults (Mage = 23.84; SD = 3.21; 50% identified themselves as women) who completed online self-assessment measures. Results showed significantly greater PSNSU, hypomentalization, childhood emotional abuse, and both attachment avoidance and anxiety among women. Indeed, within the network analysis, performed separately for men and women, network-specific associative patterns were observed; yet also similarities have emerged. Within the women's network, differently from males, attachment avoidance connects, through attachment anxiety, to emotional abuse, mood modification related to PSNSU, and hypomentalization. Nonetheless, hypomentalization was central in both networks, functioning as a hub between attachment anxiety, the PSNSU cluster, and the childhood maltreatment cluster. These results shed light on the use of social network sites as a potential maladaptive emotion regulation strategy, particularly among women. In this regard, the role of RF should be considered as a key treatment target to reduce PSNSU and support the use of adaptive emotion regulation strategies